The present invention relates to techniques for absorbing and scattering a sound.
In acoustic spaces of halls, theaters, etc., acoustic structures for scattering sounds are installed in order to remove acoustic interferences, such as flutter echoes. Japanese Patent Application Laid-open Publication No. 2002-30744, for example, discloses an acoustic structure, in which a hollow space is formed to extend in one direction, and in which a plurality of members, each having an opening that allows the hollow space to communicate with an external space are arranged. Once a sound wave enters the hollow space, it is re-radiated through the openings of the members, so that a sound scattering effect can be achieved.
With a relatively small space, such as a living or sitting room of an ordinary house, a meeting room or a music room, it is required to achieve not only an appropriate sound scattering effect but also an appropriate sound absorbing effect. However, if an acoustic structure for achieving a sound scattering effect and an acoustic structure for achieving a sound absorbing effect are provided separately in a limited space, the separate acoustic structures would take up much of the space. Further, if an acoustic structure is made using a porous sound absorbing material, such as felt, with a view to enhancing a sound absorbing effect for low frequency bands, the acoustic structure would increase in dimension in its thickness direction and thus further narrow the limited space.